Section: New Results

Tools Infrastructure

Participants : Stéphane Ducasse, Simon Denier, Nicolas Anquetil, Jannik Laval.

Reengineering large applications implies an underlying tool infrastructure that can scale and also be extended.

Supporting multiple source models efficiently. When reengineering large systems, software developers would like to assess and compare the impact of multiple change scenarios without actually performing these changes. A change can be effected by applying a tool to the source code, or by a manual refactoring. In addition, tools run over a model are costly to redevelop. It raises an interesting challenge for tools implementors: how to support modification of large source code models to enable comparison of multiple versions. One naive approach is to copy the entire model after each modification. However, such an approach is too expensive in memory and execution time. In [21] we explore different implementations that source code metamodels support multiple versions of a system. We propose a solution based on dynamic binding of entities between multiple versions, providing good access performance while minimizing memory consumption.

Metamodeling at work. Object-oriented modelling languages such as EMOF are often used to specify domain specific meta-models. However, these modelling languages lack the ability to describe behavior or operational semantics. Several approaches have used a subset of Java mixed with OCL as executable meta-languages. In [11] we show how we use Smalltalk as an executable meta-language in the context of the Moose reengineering environment. We present how we implemented EMOF and its behavioral aspects. Over the last decade we validated this approach through incrementally building a meta-described reengineering environment. Such an approach bridges the gap between a code-oriented view and a meta-model driven one. It avoids the creation of yet another language and reuses the infrastructure and run-time of the underlying implementation language. It offers an uniform way of letting developers focus on their tasks while, at the same time, allowing them to meta-describe their domain model. The advantage of our approach is that developers use the same tools and environment they use for their regular tasks. Still the approach is not Smalltalk specific but can be applied to any language offering an introspective API such as Ruby, Python, CLOS, Java and C#.